The present invention relates to a process for producing a food having excellent preservability, and a food preservative.
The storage and preservation of foods in stores and homes in the course of distribution of foods are themes required to be always solved. Various physical and chemical processes have been conceived as measures for such themes. Examples of the measures taken hitherto are freezing, refrigeration, drying, preservation in salt, preservation in sugar, heat sterilization, heat pasteurization (bottling and canning), heating packages, gas substitution of the inside of the packages, and use of a chemical preservative such as benzoic acid, sorbic acid and the like.
The safety is first of all required at all times, but in recent years, particularly, the interest in health and foods is heightened and in addition, the interest in natural foods or foods close to natural foods is growing. Such a tendency to the foods in the recent years exerts a remarkable influence to food-preserving processes.
One problem associated with the current foods is that a national boundary for foods has been eliminated, and that food materials or foods themselves have been imported from all places in all over the world. This means that various microorganisms adhering to or polluting foods have been widely brought to food markets along with the foods, resulting in indication of risks of the food poisoning caused by many new food-poisoning bacteria, e.g., E. coli O-157:H7, several salmonellae, and A-type or B-type botulinus bacilli which have been so far less detected in Japan.
Further, a wide variety of cooked foods have increased in recent years. For example, so-called subsidiary foods such as salads, sandwiches, fried eggs, chicken nugget, custard creams, boiled foods, fried foods, pickles or pickled vegetables and the like have been placed on the markets, while being demanded for the assurance of the stability against microorganisms for a given period in its own way.
It is an intention for the health to reduce the concentration of salt in all preservable foods. For example, the concentration equal to or higher than 10% of salt in salted guts of cuttlefish has been reduced to 4 to 5%; the concentration of salt in pickled vegetables in a range of 12 to 13% has been reduced to 4 to 6%; and the concentration of salt in a soybean paste, i.e., miso on the order of 13% has been reduced to 4 to 8%. This means that the stability of the foods against microorganisms has been reduced remarkably. The foods have been liable to be not merely putrefied, but also the safety against various food poisoning bacteria has been reduced.
In such a situation, the basic measures for food-preservation taken usually are as follows, for example: (1) to clean the food producing environment, (2) to reduce the pollution of foods by microorganisms to a level as low as possible at steps of producing and packing the foods, (3) to use food materials having a degree as small as possible of pollution by microorganisms, (4) to control a course from a producing step to a packing step to a temperature as low as possible, and (5) to preserve food products at a low temperature. However, it is extremely difficult to reduce the number of microorganisms in raw food materials completely to zero, and even when foods have been put at a low temperature, some of bacteria proliferate well even at the low temperature and hence, they may grow with the passage of time to putrefy the foods in some cases.
On the other hand, it is a process known from old times to enhance the preservability of foods by heating the foods. However, to carry out the perfect sterilization, a severe heating condition must be set and in such a case, the value of food itself is reduced due to the degradation of nutritious components in the food and to the loss in taste inherent in the food. For this reason, in practice, a heating condition moderate to a certain extent is set and hence, a perfect sterilization cannot be achieved. For example, fabricated foods having increased in recent years suffer from a problem of the deterioration caused by heat-resistant bacteria such as Bacillus remaining in a food after fabrication under heating of the food, and sealed foods such as a canned coffee also suffer from a problem of the deterioration caused by flat-sour spoilage bacteria. Further, a problem of food poisoning due to a secondary pollution arises frequently.
To solve these problems, a variety of techniques for enhancing the preserving food technique have been developed, and the addition of a preservative is one of such techniques. In general, the preservatives are broadly classified into a synthesized preservative designated in the Food Hygiene Law, another food additive having a food preservation effect and a naturally occurring material. However, there is a restriction on use of the synthesized preservative, and some of customers have apprehensions about the safety, particularly, an influence on a human body and hence, there is a tendency in recent years to keep a synthesized preservative from being added. Consequently, the utilization of an antibacterial substance excellent in safety and substituted for the synthesized preservative has been studied.
It is an object of the present invention to provide process for producing a food having excellent preservability, retaining quality by using an antibacterial substance excellent in safety.
It is another object of the present invention to provide a food preservative which contains an antibacterial substance excellent in safety, can enhance the preservability of a wide variety of foods and moreover, does not drop the quality, and to provide a process for preserving foods.
The further objects and advantages of the present invention will become apparent from the following description.
According to the present invention, the above objects and advantages are achieved, first, by a process for producing a food having excellent preservability, which comprises the step of heating a food, while adding 1,5-D-anhydrofructose, or the steps of adding 1,5-D-anhydrofructose to a food and then heating the food (this process may be referred to as a first process of the present invention hereinafter).
According to the present invention, the above objects and advantages are achieved, secondly, by a process for producing a food having excellent preservability, which comprises the step of adding 1,5-D-anhydrofructose previously subjected to a heat treatment to a food (this process may be referred to as a second process of the present invention hereinafter).
According to the present invention, the above objects and advantages are achieved, thirdly, by a food preservative containing
(A) one or both of 1,5-D-anhydrofructose and 1,5-D-anhydrofructose previously subjected to a heat treatment, and
(B) a substance capable of being used as a food additive and having an antibacterial activity.
According to the present invention, the above objects and advantages are achieved, fourthly, by a process for producing a food having excellent preservability, which comprises the step of adding the above-described food preservative to a food (this process may be referred to as a third process of the present invention).
According to the present invention, the above objects and advantages are achieved, fifthly, by a method for preserving a food, which comprises adding the above-described food preservative to a food and preserving the obtained food (this process may be referred to as a fourth process of the present invention).
The further objects and advantages of the present invention will become apparent from the following description.